The invention pertains to the field of sewers, storm water drains and sewage treatment. In particular, the invention pertains to means for directing normal sewage flow in large combined storm water and sewerage drains into sanitary interceptor sewers and for causing large storm water flow to bypass the interceptor connection thereby protecting the sewage treatment facility from sudden storm water surges.
U.S. Pat. No. 3,604,728 discloses a drip irrigation device to permit a small portion of the water flow to be tapped off for leakage into the surrounding soil. The device can be formed integral with the lengths of irrigation pipe, however, there is no suggestion that low flow rates be tapped and high flow rates in the pipe not be tapped.
U.S. Pat. No. Re. 29,996 discloses a combined aerobic and anaerobic sewage treatment tank having an entrance trough leading to a weir with a hollow vertical channel. Here again there is no suggestion that low flow rates of liquid be diverted from the vertically hollow channel and high flow rates be not diverted.
Currently used diverters for directing sewerage flow from a combined storm water and sewage drain to an interceptor comprise a large concrete structure adjacent the storm drain and a connection from the concrete structure to the interceptor. The storm drain contains a diversion weir and an outlet pipe leading to the concrete structure. Controlling flow of sewage into the concrete structure is a mechanical gate which regulates the flow by a float and chain mechanism. The float, chain and gate are typically of metal and subject to failure from corrosion, metal fatigue, clogging and jamming. As a result the current diverters are expensive to manufacture, install, and maintain. Because the storm and sewage drains for a medium size city may require fifty or more diverters, installation and maintenance are significant budget items.
Tipping plate regulators have also been used to limit storm water flow from entering sanitary interceptors, however, the mechanical parts are also in contact with raw sewage and therefore subject to high maintenance cost. Small amounts of sludge or small increases in friction cause the tipping plates to cease to function.
Hydro-brake regulators comprise a set of vanes that impart high resistance to large flows entering the interconnect to the sanitary interceptor while permitting low flows to pass through almost unimpeded. The hydro-brake regulators, however, permit flows greater than peak sanitary flows.
With a view toward substantially reducing diverter maintenance and installation costs, applicant has invented the new diverter disclosed in the following description.